The present invention relates to a foldable keyboard which is excellent in portability and easy to operate during use and, more particularly, to a foldable keyboard capable of bringing three keyboard units from a folded state into a horizontally aligned state, and vice versa, by a simple one-touch operation, and capable of positioning the keyboard units in a folded state that prevents release of the folded state of the units during carrying, thus improving the portability thereof.
Heretofore, various types of foldable keyboards have been proposed. Such keyboards are generally constructed so that a plurality of keyboard units are arranged one above another in a folded state during non-use and, alternatively, are aligned in a horizontal state during use.
For example, Japanese unexamined patent publication No. Hei 8-190834 discloses a folding keyboard constructed of three keyboard blocks A1, A2, and A3, the keyboard blocks A1 and A2 being mutually connected by means of a link B1 and the keyboard blocks A2 and A3 being mutually connected by means of a link B2.
In this keyboard, the three keyboard blocks A1-A3 can be folded during non-use by action of the links B1 and B2, and the keyboard blocks A1-A3 can be aligned in a horizontal state during use, similarly, by action of the links B1 and B2. The keyboard when folded can be reduced in area to one half or one third the area of the entire keyboard (unfolded). Thus, the size of the keyboard can be reduced in conformity to a downsized computer main unit or the like.
However, the folding keyboard disclosed in Japanese unexamined patent publication needs the following steps to unfold the keyboard blocks A1-A3 into a horizontally aligned state during use; at first, the blocks A1 and A2 are rotated (unfolded) with respect to the lowermost block A3 while allowing a support shaft of the link B2 to slide in a slit C2 of the block A2, and then the block A1 is rotated (unfolded) with respect to the lower block A1 while allowing a support shaft of the link B1 to slide in a slit C1 of the block A1.
In this way, each of keyboard blocks A2 and A1 requires rotating and sliding motions in order to fold or unfold the keyboard. Such unfolding work has a drawback in that it cannot be performed by a one-touch operation.
The folding keyboard disclosed in the above Japanese unexamined patent publication No. Hei 8-190834 can achieve downsizing of the keyboard itself; however, this keyboard does not securely position the keyboard blocks A1-A3 and therefore the folded blocks A1-A3 may be loosened during carrying. This may lose one half its effectiveness of attempting improvement of portability by constructing the blocks A1-A3 as foldable.